GarageBand audio delete

Hey all,

For a school paper I had to interview someone extensively about a certain topic, which as a reporter I would have normally just written these responses, but as I said this interview was pretty extensive and I had it all recorded instead on GarageBand, since I couldn't find any other program in Applications to record from.

Anyhow, I just used the audio mic to record in the Macbook and afterwards minimized the file, after saving it, and opened it up 4 days later to transcribe the conversation. However, as I was trying to cut the audio so I wouldn't have to rewind every 10 seconds, I though I had selected a specific region but ended up deleting the entire conversation audio. I frantically tried to reverse the delete but it said it couldn't undo the delete. I tried searching for the audio file but cannot find it. Did garage band really let me accidentally delete an important recording and not have an option to retrieve it? I'm also confused as to why saving the project did not save the audio file.

I'm not familiar with this program at all so trying to do anything is foreign to me. If anyone could help that would be immensely appreciated.

Thanks